Pream question

A few days ago I got Audio Research LS-5 MKII for testing. The sound seems good for me so I decided to buy it. But right now there are two more preamps in the same price range at our local market: Audio Research LS-25 MKII and Balanced Audio Technology VK-51SE. All have quite positive feedbacks... What will be the best choice among these three?

My current system is: B&W Matrix 803 S2, Luxman Da-06 DAC and Luxman M600-A amp.
Strange that the BAT 51 and the LS-25 should be the same price used. The BAT was a $10k unit when new and the LS-25 a $5500 unit.

I'd get the BAT, if you can deal with the heat from the eight 6H30P valves. I hope it comes with the remote, though.

I think that the LS-25 may be a touch too dry with your B&Ws.

The easiest way to do this, is to listen to all 3 and pick the one that sounds the best.
All three could be quite old.
Whichever you choose, you'll probably want to send back to the factory for an inspection (caps in particular).
It's quite a problem to be able to listen to the used amps. Not many sellers are ready to give a "trial period"... The same is with sending to the factory for an inspection - the overseas shipping is rather expensive and noone can guarantee that the amp survives it well.

As I understand the BAT should be the newest one among all three?
Sorry, but you did say the preamps were in your local market. I thought that meant you had access to them. If I had to buy blind, the BAT is probably the safest choice. I had the LS25 and its not the best match for your tweeter. The BAT has a nicer top end and the build quality is much better. But you're still taking a chance. You should try to listen to it first, if you can.
My guess is they've been making the VK-51SE almost 20 years.
The internet (or BAT) can tell you for sure...
So I'll try VK-51SE. Looks like it's one of the best choise for such money)
I think you'll be very happy with it. It sounds great and the build quality is outstanding.
I was able to listen to VK-51SE and I wasn't impressed at all... The sound was absolutely dead and flat. Could it be because of the dying tubes? I'll try to persuade the seller to give it to me for a few days for the tests with my system. But right now LS-5 MKII sound really much better...
You won't hear the 51SE at its best unless you spend the "big dough" and get some NOS "DR" 6H30 tubes (talk to BAT). I tried some new production tubes which gave dreadful sound (and died within three months).
Nobody said the high-end is easy...
Can anyone tell me what caps should I use for 51SE as a replacement? Is it 0.1uf 400v or 1uf 400v by Jensen?
How do you know that the caps are the problem? I know that I recommended the Bat, but sometimes things don't work out. I was kind of surprised that it didn't sound good for you. The last thing I would recommend for you to do is put money into an expensive preamp that you've never heard sounding good. There's other choices, and not only that, you really don't know if there is anything wrong with it.

That said, if you want to look into Caps, I would contact Bat. They're known for offering Cap upgrades, and if you explain to them the problem, they may be able to give you some good advice. Bat does have a very good reputation. I don't think they would mislead you in any way just to sell a preamp.
Like talking to the wall...
There is a permanent noise coming from the left block of caps. I took the amp to the service center and I'm waiting for their conclusion. In case the problem is with caps - it's better to start searching for the replacment parts now as I doubt that it will be possible to find the original Jensen in our country)

Btw I replaced all the tubes with Electro-Harmonix 6H30Pi EHG. The sound is better now but still far from LS5ii imo...
While both the BAT and ARC are fine preamps, having heard both myself I'd say the difference in their characters is very marked. The BAT is very neutral, closer to a really good solid state unit than the classic tube sound. The LS5, on the other hand, is probably the closest thing to a classic tube-sounding preamp that ARC made since the SP10; as a result, it has a lot of admirers. It seems to me from what you've written so far that you prefer the classic tube sound, so I'd suggest you stick with the LS5. Re-capping the BAT will change its sound, but I don't think you'll get it to change its character that much, only improve on its existing character. Just MHO.
Everything is well with CAPs - the problem was with bad soldering. That's a good news)

Spent some money and got NOS P-DR tubes. Will try them during the weekend...
Well maybe something is wrong with my ears or with my system or with BAT amp... The new DR tubes made the sound better (a crazy price for 35 years old soviet stuff btw...) but still I'm not satisfied. The sound of LS5 is more detailed, more "surrounding" imo. Also the volume level of BAT isn't so high: it's absolutely comfort to listen with 50% of maximum level while with LS even 30% is very loud.

Should I give the new tubes more time to play? Could it be the problem because of using rather simple step down transformer?

I don't want to return or to sell BAT right now - at least it looks rather good)